1. Field of the Invention
This invention relates to a coupling for engaging two rotary shafts. More particularly, this invention relates to a drill motor coupling for connecting two misaligned rotating shafts in an oil or gas well.
2. Description of the Prior Art
Downhole drill motors are more frequently used to drill oil and gas wells. Typically, such motors are driven by drilling mud which is forced down the drill string. Such drill motors connect with a drill bit by means of a rotary shaft. From time-to-time the drill bit may be misaligned with respect to the drill motor. Therefore, it is necessary at times to use one or more couplings in the shaft to accommodate the chances of misalignments. Additionally, such couplings need to accommodate compressive load while the drilling mud is moving downwardly and tensile loads during a reverse circulation.
The use of flexible motor couplings is well known. See, for example, U.S. Pat. Nos. 5,205,789 and 4,976,655. However, such designs are relatively complex to manufacture and can be difficult to assemble in the field. Consequently, there is a need for an improved design which can maximize manufacturing efficiencies, minimize cost and simplify field installations.